The patch titled Subject: kernel/timer.c: use debugobjects to catch deletion of uninitialized timers has been added to the -mm tree. Its filename is kernel-timerc-use-debugobjects-to-catch-deletion-of-uninitialized-timers.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ From: Christine Chan <cschan@xxxxxxxxxxxxxx> Subject: kernel/timer.c: use debugobjects to catch deletion of uninitialized timers del_timer_sync() calls debug_object_assert_init() to assert that a timer has been initialized before calling lock_timer_base(). lock_timer_base() would spin forever on a NULL(uninit-ed) base. The check is added to del_timer() to prevent silent failure, even though it would not get stuck in an infinite loop. [sboyd@xxxxxxxxxxxxxx: remove WARN, intialize timer function] Signed-off-by: Christine Chan <cschan@xxxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: John Stultz <john.stultz@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Stephen Boyd <sboyd@xxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- kernel/timer.c | 53 ++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 48 insertions(+), 5 deletions(-) diff -puN kernel/timer.c~kernel-timerc-use-debugobjects-to-catch-deletion-of-uninitialized-timers kernel/timer.c --- a/kernel/timer.c~kernel-timerc-use-debugobjects-to-catch-deletion-of-uninitialized-timers +++ a/kernel/timer.c @@ -487,12 +487,40 @@ static int timer_fixup_free(void *addr, } } +/* + * fixup_assert_init is called when: + * - an untracked/uninit-ed object is found + */ +static int timer_fixup_assert_init(void *addr, enum debug_obj_state state) +{ + struct timer_list *timer = addr; + + switch (state) { + case ODEBUG_STATE_NOTAVAILABLE: + if (timer->entry.prev == TIMER_ENTRY_STATIC) { + /* + * This is not really a fixup. The timer was + * statically initialized. We just make sure that it + * is tracked in the object tracker. + */ + debug_object_init(timer, &timer_debug_descr); + return 0; + } else { + setup_timer(timer, stub_timer, 0); + return 1; + } + default: + return 0; + } +} + static struct debug_obj_descr timer_debug_descr = { - .name = "timer_list", - .debug_hint = timer_debug_hint, - .fixup_init = timer_fixup_init, - .fixup_activate = timer_fixup_activate, - .fixup_free = timer_fixup_free, + .name = "timer_list", + .debug_hint = timer_debug_hint, + .fixup_init = timer_fixup_init, + .fixup_activate = timer_fixup_activate, + .fixup_free = timer_fixup_free, + .fixup_assert_init = timer_fixup_assert_init, }; static inline void debug_timer_init(struct timer_list *timer) @@ -515,6 +543,11 @@ static inline void debug_timer_free(stru debug_object_free(timer, &timer_debug_descr); } +static inline void debug_timer_assert_init(struct timer_list *timer) +{ + debug_object_assert_init(timer, &timer_debug_descr); +} + static void __init_timer(struct timer_list *timer, const char *name, struct lock_class_key *key); @@ -538,6 +571,7 @@ EXPORT_SYMBOL_GPL(destroy_timer_on_stack static inline void debug_timer_init(struct timer_list *timer) { } static inline void debug_timer_activate(struct timer_list *timer) { } static inline void debug_timer_deactivate(struct timer_list *timer) { } +static inline void debug_timer_assert_init(struct timer_list *timer) { } #endif static inline void debug_init(struct timer_list *timer) @@ -559,6 +593,11 @@ static inline void debug_deactivate(stru trace_timer_cancel(timer); } +static inline void debug_assert_init(struct timer_list *timer) +{ + debug_timer_assert_init(timer); +} + static void __init_timer(struct timer_list *timer, const char *name, struct lock_class_key *key) @@ -909,6 +948,8 @@ int del_timer(struct timer_list *timer) unsigned long flags; int ret = 0; + debug_assert_init(timer); + timer_stats_timer_clear_start_info(timer); if (timer_pending(timer)) { base = lock_timer_base(timer, &flags); @@ -939,6 +980,8 @@ int try_to_del_timer_sync(struct timer_l unsigned long flags; int ret = -1; + debug_assert_init(timer); + base = lock_timer_base(timer, &flags); if (base->running_timer == timer) _ Subject: Subject: kernel/timer.c: use debugobjects to catch deletion of uninitialized timers Patches currently in -mm which might be from cschan@xxxxxxxxxxxxxx are debugobjects-be-smarter-about-static-objects.patch debugobjects-extend-to-assert-that-an-object-is-initialized.patch kernel-timerc-use-debugobjects-to-catch-deletion-of-uninitialized-timers.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html